Hi welcome to HCMForum. The problem you are facing is anxiety neurosis
. Your mind is not accepting the deed you are doing.
Due to involuntary action of the penile vein valves you are having this negative effect. You are expected to have psychological
treatment for no fault. If drag the same process with out treatment it may become habbit in your marietal life. I advise you
to avoid pre marietal sex. It wont suit to some people. Dont worry you will be fine if you can avoid PMS.